1. Field
The present invention relates to an air filter having a balanced seal and a dust collector for use with same.
2. Description of the Related Art
In many dust collecting systems, an air filter with a rectangular flange is employed. The rectangular flange extends beyond the periphery of the air filter and provides a surface for mounting the air filter to the dust collector. The air filter is mounted to the dust collector by clamping the air filter to a tube sheet disposed in the dust collector which separates dirty and clean air plenums. Dirty air entering the dirty air plenum of the dust collector passes through the air filter to remove particulate entrained in the dirty air. The filtered air exits the air filter and passes through a hole in the tube sheet into the clean air plenum, from which the filtered clean air is exhausted to atmosphere from the dust collector. The air filter is sealed to the tube sheet by means of a clamp which engages the flange of the air filter. In many systems, the clamping mechanism comprises two parallel clamping bars which may be actuated toward the tube sheet, thereby engaging the flange and compressing a gasket mounted to the flange against the tube sheet, thereby creating a seal between the air filter and the tube sheet. To provide good engagement between the clamping mechanism and the flange of the air filter, the flange is typically square or rectangular.
FIG. 1 illustrates a top perspective view of a conventional air filter 100. The air filter 100 includes a cylindrical filter element 110 bounded by an end cap 106 at a first end and a rectangular flange 104 at a second end. The rectangular flange 104 is shown in FIG. 1 as having two short edges 112 and two long edges 114. The rectangular flange 104 includes an aperture 120 to allow air passing through the filter element 110 to exit the filter 100 and a ring shaped recessed channel 130 for receiving the filter element 110.
At least one circular gasket 108 is coupled to the rectangular flange 104 generally on the backside of the recessed channel 130, which is located well inward of the perimeter of the rectangular flange 104. The gasket 108 closely circumscribes the aperture 120 to seal the filter 100 against a mounting surface (not shown FIG. 1). The circular gasket 108 is laterally well spaced from an edge 112 of the flange 104; generally directly above the filter element 110 potted in the recessed channel 130.
The filter 100 is conventionally secured to the mounting surface applying a force to an area 116 located immediately along the long edges 114 of the flange 104. In FIG. 1, the area 116 extends about 1-2 inches inward from the long edges 114 of the flange 104, as shown by imaginary dashed lines 122. As a result, as the clamping mechanism engages the area 116 of the flange 104 along the long edges 114, the clamping force must be transferred laterally through the flange 104 to the gasket 108. As a result, the gasket 108 is loaded non-uniformly which may contribute to potential leakage. For example, a region 118 of the gasket 108 closest to the short edges 112 has less loading then a region 124 of the gasket closest to the long edges 114. Additionally, the offset between the area 116 that clamping force is applied to the location when the gasket 108 is loaded may cause the flange 104 to further deflect along the short edges 112, further contributing to non-uniformity of the sealing force applied to the gasket 108 and further increasing the potential for air bypassing the filter 100.
Therefore, there is a need for an improved air filter with a balance seal which improves the uniformity of the clamping force.